Geek stuff – Page 88 – a sibilant intake of breath

Obama changing tack on missile defence

In a surprising announcement, it seems that the United States may give up plans to put RADAR sites and/or interceptors in Poland and the Czech Republic. These sites would have been ideally suited to track and intercept ballistic missiles launched towards the United States from Iran. This is a reversal of the position President Obama adopted in April, when he gave a speech in Prague. The most plausible reason for the shift is an accommodation with Russia, which has always staunchly opposed US ballistic missile defence (BMD) plans, and which holds key levers when it comes to Iran and nuclear technologies. Notably, the sites in Poland and the Czech Republic would not be especially well placed to aid in the interception of Russian missiles, which would anyhow be too numerous and sophisticated to be plausibly neutralized through a BMD system.

The shift probably signals both the resurgence of Russia as a regional power and the decline of American flexibility that has accompanied ongoing involvement in Iraq and Afghanistan. The US may also be reckoning that it is a better strategic move to try to block Iranian acquisition of nuclear weapons, with Russian help, than to try to field a system to destroy deployable versions of these weapons if and when they exist. Iran’s successful satellite launch in February suggests that they could develop nuclear-capable missiles with a long-range capacity, provided they are able to sufficiently miniaturize their nuclear weapons: an undertaking that proved very challenging even for the United States.

While Poland and the Czech Republic are usefully positioned between Iran and the east coast of North America, Japan is best positioned between North Korea and the west coast. Given the strength of the US-Japanese alliance, and the domestic concern about North Korea and China in Japan itself, it seems likely that the Pacific version of the BMD system will continue to develop. When I visited USNORTHCOM, the US Strategic Space Command, and NORAD, all of their missile defence examples concerned North Korean launches.

[Update: 4:24pm] To clarify the above, it seems the American plan was to put X-band RADAR facilities in the Czech Republic and ten SM-3 interceptor missiles in Poland.

CAPTCHAs

Like many web users, I am of two minds about Completely Automated Public Turing test to tell Computers and Humans Apart (CAPTCHAs). On the one hand, I see their importance in fighting several types of spam. In particular, they are an important defence against the spam blogs that have become so prevalent recently. These sites are set up based on a high-value keyword. They then trawl through real blogs, copy content, and put it up. To Google, this looks like a real blog specializing in that keyword. People find it through Google searches, and sometimes end up clicking the ads that are invariably strewn across these robot-created sites.

When it comes to creating new blogs and email accounts, I find CAPTCHAs entirely reasonable.

Where I object is with more mundane uses, such as vetting comments on blogs. Using a CAPTCHA can seriously annoy readers: especially those who have poor vision, or who are using browser add-ons like NoScript for extra security. To me, when a blog owner chooses CAPTCHAs as a security feature, they are saying that they are happy to waste the time of all of their commenters, rather than invest a bit of their own setting up a spam filtering system and occasionally checking for false positives and false negatives. If your blog gets 5,000 comments a day, you have a good excuse. If it gets less than 20, it really seems like a combination of Akismet and some .htaccess rules should be just fine.

reCAPTCHA (which Google recently purchased) has at least two redeeming features. For one, it does useful work. Unlike most CAPTCHAs, which simply garble text for users to decipher, reCAPTCHA uses text from real documents being scanned. It gives users two words to decipher: one known word to perform the CAPTCHA function, and one unknown word for use in digitizing the book. This leads directly to the second good feature: since these books have already been scanned by the best optical character recognition (OCR) software available, they are fundamentally protected against automated CAPTCHA attacks. Of course, you can always pay real people a small fee for solving the puzzles. reCAPTCHA is thus a relatively robust system, against automated attack, with the additional benefit of adding to the sum of useful digitized information.

Hopefully, future CAPTCHA systems will be less annoying for users and more difficult for computers to game. Experimental forms have included tasks like picking out only kittens from photos showing a number of types of animals. This is apparently a task that is easy for humans, but quite beyond the capability of automatic image recognition software.

Personally, I prefer to think of them as Computer Automated Person Checking Algorithms. It lacks the Turing shout-out, but is more concise and comprehensible.

Russia and the Iranian bomb

Apparently, one of the key limiting factors in the Iranian nuclear program is access to uranium. Domestic supplies are limited and of low quality. As such, Iran is heavily dependent on Russia to provide feedstock for its centrifuge-based enrichment program, as well as its Bushehr reactor. For instance, Russia provided 82 tons of low-enriched uranium in February, to allow the initial loading of the reactor.

For those who hope to do so, stopping an Iranian bomb therefore has much to do with convincing Russia to reduce support. Apparently, one thing the Russians want is for Israel to loosen the strong defence relationships it has built with Ukraine and Georgia. Given that Israel has the most to fear from an Iranian bomb – and that they are one of two states that could plausibly use military force to try to disrupt the Iranian atomic effort – this dynamic is a significant one.

As Stephanie Cooke’s book discussed, the proliferation of nuclear weapons has always been associated with the wrangling of great powers. It remains to be seen what outcome will result in this case.

(Note: It would be appreciated if commenters could refrain from any political tirades, if they feel inclined to discuss this. I am sometimes hesitant to post anything related to the Middle East, out of discomfort about the shrill responses any mention of the region can provoke.)

Keep your flash in your pants

The other day, I attended some live music at the Umi Cafe on Somerset. Throughout the multi-hour performance, there was a cadre of amateur photographers – some with point and shoot cameras, some with dSLRs – happily snapping away. Almost without exception, every shot was accompanied by a bright white flash. There are two major reasons why photographers should avoid this pattern of behaviour.

Firstly, it produces ugly and unnatural pictures. Using a flash is akin to looking at a scene with a bright white miner’s lamp on your head. This is problematic for several reasons: (a) it lights close things much more than far ones, leading to blinding white foreground objects and black backgrounds; (b) it throws very harsh shadows, leaving a person’s nose looking like a mountain on the moon; (c) the light from the flash is a different colour from incandescent or fluorescent lighting, making the scene look oddly discordant in colour.

Secondly, it really annoys people. While the ‘stadium full of flashes’ effect is a Hollywood cliché, the actual impact of using lots of flashes – especially in a small and intimate environment – is to impose your weird lighting preferences on an entire room full of people, many times a night. Flashes are distracting and rude, and should only be deployed when really necessary.

There are easy ways to avoid using the flash. First and foremost, don’t use your camera in full auto mode. With no guidance, it will usually decide that the pop-up flash is the safest way to get a usable photo. With just a bit of thinking, you can usually do better.

The first way is to increase the ISO setting on your camera. This basically makes it more sensitive to light. While doing so will make your pictures grainier, they will look a lot more natural than ‘headlamp effect’ flash shots. If you don’t know how to do this, check your manual or search online. With most point and shoot cameras, and all dSLRs, it is a fairly simple procedure. Many cameras even have a dedicated button for it. On a point and shoot camera, try cranking it up to 400 or so. On a dSLR, don’t feel shy about using 1600 ISO, or even faster. Here is an example of a high ISO photo taken with a cheap P&S camera. A flash photo of the same scene would have been infinitely worse.

The second way is to brace your camera somehow. If you have a two-second timer, this can be easily achived. Just frame the shot, with the camera sitting on the edge of a table, wall, or solid object. Then, press the shutter and then leave the camera still to take a photo. Anything moving will probably show some motion blur, but you are once again likely to produce a nicer and more natural image than you would with a flash. Tripods are also an excellent idea, and there are tiny little tabletop ones that can be easily carried around and used with a point and shoot camera. I used the combination of a $180 Canon P&S camera and a $5 tripod to take these photos: Montreal, Ottawa, Morocco, Paris, Istanbul. A great trick for churches and other buildings with interesting ceilings is to put your camera flat on the ground with a timer set, press the shutter, and step back. I used that trick to take these: Oxford, Istanbul.

People think about photographs as something you ‘take’ by pointing a camera at something and pressing the shutter. In fact, it makes more sense to think about photos as something you ‘make’ using a combination of light, gear, and intelligence. By putting some thought and effort into things, you can produce more natural photos in intimate settings, without temporarily blinding and annoying everyone around you.

Paths to geoengineering

For a number of reasons, geoengineering is all over the news. The basic idea is to counteract the effects of climate change induced by greenhouse gasses. This can be accomplished in two basic ways. One is to use a separate mechanism to reduce the amount of energy the Earth absorbs from the sun. Orbiting mirrors and sulfate injection seek to do this. This approach is not ideal, partly because it would cause unknown side effects and partly because it would not stop the oceans from becoming more acidic. A more appealing route focuses on actively removing greenhouse gasses from the atmosphere.

The first way to do this is to encourage the growth of biomass. This is relatively easy, but has limited potential. Biomass is like a giant carbon cushion: it can be thick or thin, but it cannot keep growing forever. Increasing the amount of biomass on Earth could draw down the amount of CO2 in the atmosphere a bit, but only if we also manage to cut our greenhouse gas emissions to practically zero.

The second way – mentioned before – is to draw greenhouse gasses from the air and bury them, using carbon capture and storage technology (CCS). This could be done in two basic ways: (a) draw carbon dioxide (CO2) directly from the air and bury it or (b) grow biomass, burn it, collect the CO2, and bury that. The major limitations here are cost and technology. It remains unclear whether CCS can be made safe, effective, and affordable. It is also unclear whether it could be ramped up to a big enough scale to stop catastrophic climate change, in the absence of strong mitigation action.

The third option is to enhance the weathering of rocks. In the long term, this is where atmospheric CO2 actually ends up going. Some people are talking about speeding up the process, using various suitable types of rock and various mechanisms for increasing its rate of reaction with atmospheric CO2. Once again, the uncertainties concern scale and cost.

The three options that actually remove CO2 from the atmosphere are much more appealing than options that try to interrupt incoming sunlight. Each acts directly on the cause of anthropogenic warming, rather than trying to counter it by proxy. This is a bit like removing poison from a person’s body, as opposed to administering a supposed antidote with unknown effectiveness and side effects.

It remains unknown whether there will ever be a point where geoengineering is less costly per tonne of CO2 than various mitigation approaches. Right now, there are certainly greater opportunities in areas like energy efficiency and building design. That being said, research into CO2-removing technologies strikes me as having merit. They may eventually prove economically comparable to more expensive mitigation options; they may allow us to counteract activities that inevitably produce emissions, such as air travel; and they could give us some last-ditch options, if we find ourselves experiencing abrupt, catastrophic, or runaway climate change as a result of past emissions.

Cloud computing and consumers

Writing in The Guardian, Cory Doctorow provides a good explanation of why cloud computing might not be so great for individual users. Basically, companies are hoping to use it to wring more money from people, for services that were previously free. As he explains:

[T]he main attraction of the cloud to investors and entrepreneurs is the idea of making money from you, on a recurring, perpetual basis, for something you currently get for a flat rate or for free without having to give up the money or privacy that cloud companies hope to leverage into fortunes.

That’s not to say there aren’t potential advantages. It may well be worth a montly fee for well implemented and highly secure backup, especially for those who aren’t too computer savvy or don’t have access to Apple’s excellent Time Machine product. (Doctorow talks about using Amazon’s S3 service and the Jungle Disk tool.)

Really, backup seems like the cloud computing application with the most value for users, since encrypted backups elsewhere will probably be safe if you are robbed or have your house burn down. Another application with more limited utility might be buying access to huge amounts of computing power, which could be useful for some researchers.

Incidentally, Time Machine isn’t quite good enough for protecting irreplaceable physical data, since your external hard drive could be destroyed in an accident at the same time as your computer, or stolen. While I use Time Machine for daily backups, I also back up critical files (such as my photos) to a hard drive I keep at work and update every few months. A fairly easy way to do this is to keep all your irreplaceable documents in one place – such as username/documents/original/ – and then copying it over to the third drive every few months. rsync is an ideal way to do this, but it isn’t very user friendly.

An apology for Alan Turing

In addition to being one of the most notable mathematicians and computer scientists in British history, Alan Turing played a key role in cracking German codes during the Second World War. Despite the importance of his contribution, and the role intelligence from the Government Communications Headquarters (GCHQ) played in helping the allies in the Battle of the Atlantic, Turing was subsequently persecuted by the British authorities for being homosexual.

Turing was stripped of security clearance, criminally prosecuted for consensual sex with another man, chemically castrated with estrogen injections, and eventually driven to depression and suicide.

Recently, a petition was launched insisting that the “British Government should apologize to Alan Turing for his treatment and recognize that his work created much of the world we live in and saved us from Nazi Germany. And an apology would recognize the tragic consequences of prejudice that ended this man’s life and career.” An apology for both his specific treatment and the general persecution of homosexuals seems entirely in order. Hopefully, the government will bow to the petitioner’s request, despite Turing not having any surviving family to apologize to.

While writing a historical wrong is a valid reason for issuing an apology, the incident is also not without contemporary relevance. Just look at the continued policy within the US armed forces to dismiss gay linguists from the military. Once again, people making a significant contribution to national security are being discriminated against on the basis of characteristics that are none of their government’s business.

[Update: 10 September 2009] Admirably, British Prime Minister Gordon Brown issued an apology to Alan Turing: “While Turing was dealt with under the law of the time and we can’t put the clock back, his treatment was of course utterly unfair and I am pleased to have the chance to say how deeply sorry I and we all are for what happened to him. Alan and the many thousands of other gay men who were convicted as he was convicted under homophobic laws were treated terribly. Over the years millions more lived in fear of conviction.” The full statement is on the Prime Ministerial website.

FOGBANK and American fusion bombs

The United States may have forgotten how to make FOGBANK: a critical component in at least some thermonuclear weapons. FOGBANK is an ‘interstage material’ that gets turned into a superheated plasma by the detonation of the ‘primary’ fission bomb, helping to ignite the ‘secondary’ fusion reaction.

Some speculate that FOGBANK resembles aerogel. Others describe efforts to re-learn how to make it.

But we never write anything in French…

At work, we all have confusing ‘multi-language’ keyboards, covered with accented letters for French and with important keys (such as pointy brackets) moved to strange locations.

Thankfully, you can just tell Windows to behave as though the keyboard has a standard US layout – a neat way of confirming that you really do have the entire layout memorized. As for me, I think I am ready for my blank keyboard.

The P Versus NP Problem

There are some sorts of problems where it is relatively easy to check that a solution is correct, but hard to find that solution to begin with. For example, it is easy to check whether a large number is the product of two primes (429,496,729 = 19 X 22,605,091), but it is hard to find the factors of a large number. These problems are called ‘NP problems’ in mathematics, because they cannot be solved in polynomial time.

By a quirk of mathematics, if anyone ever comes up with an efficient way to solve one of these NP problems, the technique will be applicable to all such problems. That said, it may be the case that there is no efficient way to solve any of these problems. As such, whether all or none of them are efficiently soluble is an important question in mathematics.

The importance of the problem extends beyond the theoretical realm. For instance, the ‘traveling salesman’ problem is NP. There is a salesman who wants to visit X cities, with as little travel as possible. Finding the quickest route becomes dramatically more difficult as the number of cities increases. If someone could solve the P versus NP problem they could either help Fedex and UPS a lot (if an efficient solution to NP problems is found) or prove that their work will always be challenging (if it is proven that there are none).

This article provides more information on the P versus NP problem.